On Mon, Jul 30, 2012 at 10:41 AM, Simon Fraser <smfr@me.com> wrote:
>> There's nothing problematic here spec-wise. You do precisely what it
>> says - paint the element and its descendants. If you want, you can
>> think of it like Andrew outlined - render the document as normal, just
>> skip rendering any element that's not the element() target or a
>> descendant.
>>
>> Now, this might be problematic from an implementation perspective, or
>> even from a usability perspective (it might very well not make sense
>> to paint abspos children in a different stacking context), in which
>> case we can talk about adding limitations to it. But I still don't
>> understand how anything is missing from the spec as it stands. It
>> seems like y'all are inventing problems that don't exist if you just
>> do what the spec says. ^_^
>
> I think we would have to implement as Andrew outlined. The problem for
> implementors is that painting an element does not necessarily paint all of its descendants,
> because of stacking contexts etc.
Yes, that's because the most natural notion of "descendants" in our
codebase when painting is concerned is not the same thing as the
notion of "descendants" used by CSS. That doesn't indicate a spec
problem (though it may indicate someplace where we want to change the
spec to make it easier to implement efficiently).
~TJ